The bigger thing is that the country is too big and too wealthy to be a dictatorship
Remember Russia and China have never had democratic governments and they have never been wealthy. China's wealthy is a very recent development. Other dictatorships take place is much smaller economically challenged countries.
And then our size: we are just to big for a single dictator to manage. Even with his friends controlling major networks, the internet and cell phones allow us all to be reporters. And we have access to other country's news. Honestly, he would have to turn off the internet to truly control the flow of information. Which would ruin the economy overnight. And would cause immediate civil disobedience. (Remember the outrage when tik tok was going to be banned?)
Our beloved state's rights. The fact that we have 50 states, all of them claiming some degree os sovereignty, makes it very difficult for a dictator to take charge.
I'm not saying that Trump, along with complicit Republicans, haven't caused a lot of problems. Because they have. Trump has a policy of spitefulness and up until this point Republicans have goose-stepped right behind him. As long as he suppresses reproductive rights, demonizes transgender people and doesn't make the rich pay taxes, all of the other stuff is just fine print.